One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,7)(6,8)(9,10)(11,19)(12,17)(13,21)(14,15)(16,20)(18,24)(22,23)(25,26,29,30)(27,31,35,33)(28,36,37,32)(34,39,40,38)(1,3)(2,6)(4,7)(5,8)(10,15)(12,23)(16,19)(18,21)(25,26)(27,33)(28,32)(29,30)(31,35)(34,39)(36,37)(38,40) involution — undirected(10,15)(11,20)(17,22)(18,21)(26,30)(31,33)(32,36)(38,39) involution — undirected(2,7)(4,6)(9,11,14,20)(10,16,15,19)(12,18,23,21)(13,22,24,17)(25,26)(27,31)(28,32)(29,30)(33,35)(34,38)(36,37)(39,40)(1,4,5,6)(2,3,7,8)(9,12)(10,17)(11,21)(13,19)(14,23)(15,22)(16,24)(18,20)(25,27)(26,31)(28,34)(29,35)(30,33)(32,38)(36,39)(37,40)(1,3)(2,4)(5,8)(6,7)(9,13,14,24)(10,18,15,21)(11,22,20,17)(12,16,23,19)(25,28)(26,32)(27,34)(29,37)(30,36)(31,38)(33,39)(35,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.